Malaria patients who were admitted to the Department of Infectious Diseases of the Tokyo Metropolitan Bokutoh General Hospital during the past 8 years are reviewed. Cases included 17 patients infected with Plasmodium falciparum (14 Japanese), 13 patients infected with P. vivax (9 Japanese), 3 patients infected with P. ovale (2 Japanese) and 1 Chinese patient with a mixed infection of P. falciparum and P. vivax. About 70% of Japanese patients infected with P. falciparum contracted the disease in Africa, about 90% P. vivax-infected Japanese patients contracted the disease in Asia and all P. ovale-infected patients contracted the disease in Africa. Only 13% of all (17% of Japanese) patients infected with P. falciparum who initially contracted doctors of other Japanese hospitals were correctly diagnosed, but 78% of all (67% of Japanese) patients infected with P. vivax who initially contacted doctors of other Japanese hospitals were correctly diagnosed. At present, malaria is not a rare disease in Tokyo among travelers to or from Africa or Asia.